The determination of gas and liquid flow rates and mixture densities in gas-liquid fluid mixtures is important in the oil and gas industry.
An example of an apparatus for measuring such flow rates is Schlumberger's Vx™ system (see e.g. I. Atkinson, M. Berard, B.-V. Hanssen, G. Ségéral, 17th International North Sea Flow Measurement Workshop, Oslo, Norway 25-28 Oct. 1999 “New Generation Multiphase Flowmeters from Schlumberger and Framo Engineering AS”) which comprises a vertically mounted Venturi flow meter, a dual energy gamma-ray hold up measuring device and associated processors. This system allows the simultaneous calculation of gas, water and oil volumetric flow rates in multi phase flows.
Although providing proven performance, the Vx™ system and other conventional multiphase flow meters are relatively expensive, which tends to preclude their application in “brown” field sites (i.e. oil and gas wells where capacity has fallen below about 1000 barrels/day (0.0018 m3/sec)) and other low hydrocarbon producers. However, such sites probably account for around 2-3 million oil and gas wells worldwide.